Self-discharging sludge separator



Dec. 11, 1951 A.-NYROP I SELF-DISCHARGING SLUDGE SEPARATOR Filed July11. 1947 I Invenfor: WW

Affomg/s i atented Dec. 11 1951 UN-ITED STATES PATENT OFFICESELF-DISCHARGIIGZZfSIDGE SEPARATOR Application July 11, 1947; SerialNp.760,303 In Denmark July 4, 1942 Sectionl, Public "Law 690, August 8,1946Patent expires July 4; 1962 3 Claims. l IL The present invention relatesto a self-discharging sludge separator designed to separate sludge fromone or two liquids.

More particularly the invention relates to centrifugal separators of thetype in which the bowl is divided into two parts which are adaptedto'undergo a relative axial movement at periodic intervals, to aiiordprovision for discharge of sludge between the bowlpar ts. Suchseparators are described in my prior Patent No. 2,091,329.

In the separation or various fluids and sludge it is of importance thatthe slot, or the slots, at the periphery of the bowl, and through whichthe sludge is discharged, are opened and kept in their fully openedcondition for a period sufficiently long to permit all the sludge to bedischarged. The aim of the present invention is to provide means forattaining such a desired opening of the said slot or slots.

This arrangement ensures that coarse and tough sludge which otherwisewill adhere to the sides of the separating drum is given a sufficientopening "of the slot, and sufficiently long time to be discharged fromthe bowl with as little resistance as possible.

In separators of the type in question it has been aimed to achieve arapid opening or the peripheral slots by means "of a fluid and rapidlyoperating valves, but as the time of actual discharge is very short,certain diificulties have been experienced to open the slots to theirfull extent, because pressure within the separator bowl is decreasedduring the opening.

The present invention tends not only to provide a rapid opening of theperipheral slot or slots of the bowl, but likewise to ensure a free orfull opening. 'l'his'can be attained by means of an axially disposedreciprocating member for closin said slots provided with an integral--circular flange between which and a part oi the bowl is arranged acircular groove or space that will hold some of the fluid used forreciprocating the said member.

The fluid will remain in the circular groove on account of thecentrifugal force, and will tend to actuate and force said reciprocatingmember into open position.

A complete understanding of the invention will be derived from thefollowing detailed description with reference to the accompanyingdrawing, in which Fig. 1 shows an axial sectional view of a sludgeseparator according to the invention and Fig. 2 is a detail sectionshowing a modification.

Referring to the drawing, 1 indicates the top part of a separator bowlwhich in conventional manner is screwedto the bottom parts of the bowlfor instance by means of bolts A centre tube 2 has attached thereto adischarge ring 3 carrying distributing discs 6, separating plates 5-,and an insert 8 with wings extending into the separator bowl, serving togive the fluid to be treated the same rotationalspeed as the bowl parts.The "fluid to be separated is charged through a pipe I into the centretube 2 from the lower end-of it is conveyed into the actual separatingspace. Thefiirid passes either round the lower end -of the "centre tubeand from outside in between the discs 6, or it conveyed throughapertures 43- in the lower end of the centre tube 2 upwardly through-distri butin'g holes '32 in the discs 6. During separa- 'tion thelighter components of the fluid will move centripetally between thediscs and collect in the space interior to these, "and from here bedischarged through the discharge rin 3-, whereas the heavier componentsof the fluid will pass round the exterior edge or the separa-e tingplates 5 and be discharged through one or several channels or spaces 44above the said separating plates to the discharge ring '3'. Theseheavier iluid components pass an annular weir ii 'detachaloly connectedto the upper bowl part 1. By inserting weirs of varying diameter it ispossible to regulate the separation line in the bowl between heavy andlight fluid components. If "the liquid only con'ta-insone kind of fluidthe discharge over the weir may be closed.

During separation the solid component in the fluid, if heavier than thefluid, will collect in the space near the periphery of the bowl. Thebowl has one or several slots it which are closed durin -separation ofthe solid components within the bowl by means of a reciprocable annularpiston 1'3 mounted in an annular groove the bowl which pistonperiodically is operated to uncover the slots, thus allowing the sludgecol-- lected in the separator bowl to be ejected by centrifugal "force.This annular piston t3 reciproca'tes as a piston in a =cyl-inder,'beingguided vertically "in an annular groove or channel formed between theupright, outer, cylindrical portion of the lower part it of the body andan inner part 29 positioned within said lower part. It will be notedthat the lower portion of this. fixed inner part 29 is of reduceddiameter. to provide an enlarged annular chamber [:5 ex.- tending"inwardly from the bottom of the annular groove or channel in which thepiston slides.

By means er a piston-actuating liquid conveyed to the space or chamber Iand subjected to centrifugal force, the piston is forced upwardlyagainst a gasket ID to seal the discharge slots II. The outer side ofthe upright portion of the piston I3 may be provided with integrallyformed, upper and lower, flexible and resilient lips I2 and I3 whichslide on the inner face of the upright cylindrical portion of the lowerpart I8 and serve as packing rings. Centrifugal force will throw thelips outwardly into sealing position. The inner face of the uprightportion of the piston may be sealed by a lipped resilient packing ring28 held in position on the inner part 29 by a suitable retaining ring asshown. These packings I2, Id and 28 are to prevent fluids fromby-passing the piston. The piston-actuating liquid is sprayed from atube or tubes 22 into a groove 2I and is by centrifugal force pressedinto the bottom of the space or chamber I5 through channels I9.

During the periods in which the slots II are closed a tiny jet of liquidmay be constantly sprayed into the groove 2I to provide hydraulicpressure in the space below the piston to ensure the slots I I beingheld closed during these periods.

As above noted it is important particularly when the separator ishandling matter having solids of a sticky or adhesive nature, for theslots II to be opened quickly and fully. To aid in accomplishing thataim, I provide for the quick escape of the liquid beneath the piston sothat the pressure within the separator may act on the obtuse edge 3| ofthe piston l3 to move it downwardly to open the slots II. To permit ofsuch quick release of the liquid I provide one or more relatively largeoutlets or discharge passages 26, 26 from the bottom of the chamber I5to the exterior. These passages are controlled by valves 25 which carrypistons 21 and which are of well-known type, being centrifugallyoperated to closed positions and being hydraulically operated to openedpositions.

When the discharge slots II are to be opened, the operating liquid issprayed from a tube 23 into a groove 45. By centrifugal force the liquidpasses through channels 20 to the spaces at the outer ends of thecylinders in which the pistons 2I reciprocate, the pistons being thusforced inwardly to open the valves 25. The liquid in the space orchamber I5 may then discharge through the passages 26, 26 to release thepressure on the bottom of the piston I3, so that the pressure of thefluid and solid material in the separating section of the body on theedge 3| will cause the piston to move downwardly to open the slots II.The control of the operating liquid may be a four-way valve, not shown.

As the pressure in the separating compartment on the edge 3| of thepiston decreases as soon as the slots II open, the displacement of andthe maintenance of the piston I3 in its open position will be uncertaineven when the displacement or opening movement is rapid. To remedy this,the annular groove or channel in which the piston I3 slides has theabove mentioned enlarged chamber I5 extending inwardly at the bottom ofthe guiding channel, and the piston is provided with a preferablyintegral and relatively wide radial flange I6 projecting inwardly fromits lower end into said enlarged chamber to divide this chamber into alower space below the flange and an annular, groovelike upper space I!above the flange. This wide 4 annular flange I6 has its inner edgeslightly spaced from the inner wall of the chamber so that there is anopen but restricted communication between the lower and upper spaces.Hence the working liquid entering the lower portion of the chamberthrough the passage or passages I9 will also enter the groove-like upperspace II, and there will be a tendence of the liquid above the flange tobe retained in the space II when the liquid below the flange ispermitted for rapidly discharge upon the opening of the valves 25. Thisliquid will, on account of centrifugal force, remain in the upper spaceH, and it will consequently exercise a strong hydrostatic pressuretending to force the annular piston downwardly to open position and keepit there until liquid is again admitted to the chamber through thepassages I9 for the reverse action. It will be noted that the area ofthe flange I6 in contact with the lower space is greater than that incontact with the upper space. I have found that this action of thesubstantial body of liquid retained by centrifugal force in the upperspace I'I, not only aids the quick opening of the piston to its fullyopened position but tends to hold the piston in such fully open positionso that even very tough, sticky and course solid matter will besatisfactorily ejected through the slots I I.

The groove-like upper space H is preferably made of angular shape incross-section, being narrow vertically at its largest diameter and widervertically at its smallest diameter. This may be done by forming theupper face of the flange l6 at its inner edge with an annular recess andforming a similar opposed recess in the portion of the inner part 29forming the top of the enlarged chamber, as clearly shown in thedrawings. By thus widening the inner portion of the space I! avertically thick body of liquid in the groove-like space is attained,and consequently there will be a greater downward pressure on the flangeI6 when liquid is quickly discharged from the space beneath the flange.As the piston lowers, the upper space H widens vertically and hence thewider inner portion will act as a reservoir for the narrower outerportion, and a considerable amount of the liquid will be retained bycentrifugal force above the flange I5.

I also preferably form in the piston I3 an inwardly-open, annular groove33 which opens into the reduced or narrower outer portion of the upperspace IT. This groove 33 forms a collecting pocket for any solidparticles or impurities in the piston-actuating liquid. Such impuritieswill consequently not constitute any hinderance to the reciprocation ofthe piston I3. Discharge pipes or members 3!] for continuous dischargeof semi-solid sludge may be arranged in the separator bowl.

As shown in Fig. 2 interchangeable parts 34 and 35 for replacementtogether with members 40 when worn, may be provided in the peripheralslots II.

All the functions for supplying piston actuating liquid and valvemanoeuvering liquid may be operated manually, or be arranged forautomatic operation.

It will readily be understood that the construction can be modified invarious manners within the scope of the invention as defined in thefollowing claims.

I claim:

1. A centrifugal separator, including a bowl adapted to be rotated toefiect continuous dis charge of liquid efiluents and the concentrationof suspended solid material within the bowl, and provided withperipheral slots for the intermittent discharge of concentrated solidmaterial, said bowl having a body with outer and inner portions betweenwhich is an annu .lr piston-receiving channel and an enlarged, annularchamber which extends inwardly at the bottom of said channel, an annulardischargecontrolling piston mounted in said channel for reciprocationtherein against and away from a sealing surface to control the dischargeof concentrated solid material from said peripheral slots, said pistonbeing provided with a radial flange extending inwardly from its lowerportion and into said chamber to divide the latter into a lower spacebelow said flange and an upper, annular groove-like space above saidflange, said upper and lower spaces being in open communication witheach other around the inner edge of said flange and both being adaptedto receive a piston-actuating liquid, the area of the flange in contactwith the lower space being greater than that in contact with the upperspace, means for admitting a piston-actuating liquid. into said lowerspace to act on the bottom of said flange to move said piston upwardlyto sealing position and to enter said upper space around the inner edgeof said flange, valve-controlled, quick-escape, liquid passages leadingfrom said lower space to permit the quick discharge of liquid beneaththe flange during motion of the piston downwardly to discharge positionfor concentrated solids, and valves for controlling said dischargepassages, said valves being centrifugally actuated to closed positionsand hydraulically operated to open positions, said upper groove-likespace being so proportioned and arranged that when said valves arehydraulically operated to permit of the quick escape of liquid beneaththe flange, a substantial body of liquid will be retained by centrifugalforce in the space above said flange and will exert a hydrostaticpressure tending to force said flange downwardly to assist in the quickand full opening of said piston.

2. The structure of claim 1 in which said upper groove-like annularspace has an angular cross-section, being narrow in a vertical directionat its larger diameter and wide in a vertical direction at its smallerdiameter.

3. The structure of claim 1 in which said piston is formed with aninwardly open annular groove to collect impurities in thepiston-actuating fluid, said groove opening into said groove-like upperspace at its largest diameter.

AAGE NYROP.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,091,329 Nyrop Aug. 31, 19372,126,864 Bath Aug. 16, 1938 2,178,547 Bjornstjerna Nov. 7, 19392,209,554 Bath July 30, 1940 FOREIGN PATENTS Number Country Date 715,701France Sept. 29, 1931 400,809 Great Britain Nov. 2, 1933

